Organometallic fluorenyl compounds, preparation, and use

ABSTRACT

Fluorenyl-containing metallocenes are disclosed along with methods for making the metallocenes. Also disclosed are methods for using the metallocenes as polymerization catalysts. In addition, polymers resulting from such polymerizations are disclosed.

This application is a continuation of application Ser. No. 08/352,936Dec. 9, 1994 which is a divisional of application Ser. No. 07/734,853,filed Jul. 23, 1991, now U.S. Pat. No. 5,436,305 which was acontinuation-in-part of U.S. patent application Ser. No. 07/697,363filed May 9, 1991 by three of the present co-inventors now U.S. Pat. No.5,191,132. The disclosure of said application Ser. No. 697,363 isincorporated herein by reference.

This invention relates to organometallic compounds. More specifically,this invention relates to organometallic compounds containing at leastone fluorenyl ligand. In another aspect, this invention relates topolymerization catalyst systems which contain organometallic fluorenylcompounds. In still another aspect, this invention relates to a methodfor polymerizing olefins using such organometallic fluorenyl compoundsand to the polymers resulting from such polymerizations.

BACKGROUND OF THE INVENTION

Since the discovery of ferrocene in 1951, a number of metallocenes havebeen prepared by the combination of compounds having cyclopentadienylstructure with various transition metals. The term "cyclopentadienylstructure" as used herein refers to the following structure. ##STR1##

The term "cyclopentadiene-type compounds" as used herein refers tocompounds containing the cyclopentadiene structure. Examples includeunsubstituted cyclopentadiene, unsubstituted indene, unsubstitutedfluorene, and substituted varieties of such compounds. Also included istetrahydro indene.

Many of the cyclopentadiene-type metallocenes have been found useful incatalyst systems for the polymerization of olefins. It has been noted inthe art that variations in the chemical structure of suchcyclopentadienyl-type metallocenes can have significant effects upon thesuitability of the metallocene as a polymerization catalyst. Forexample, the size and substitutions on cyclopentadienyl-type ligands hasbeen found to affect the activity of the catalyst, the stereoselectivityof the catalyst, the stability of the catalyst, and other properties ofthe resulting polymer; however, the effects of various substituents isstill largely an empirical matter, that is, experiments must beconducted in order to determine just what affect a particular variationwill have upon a particular type of cyclopentadienyl-type metallocene.Some examples of some cyclopentadienyl-type metallocenes are disclosedin U.S. Pat. Nos. 4,530,914; 4,808,561; and 4,892,851, the disclosuresof which are incorporated herein by reference.

While there are references in the prior art which have envisionedmetallocenes containing fluorenyl groups, only a very limited number offluorenyl-containing metallocenes have actually been prepared prior tothe present invention. The Journal of Organometallic Chemistry, Vol.113, pages 331-339 (1976), the disclosure of which is incorporatedherein by reference, discloses preparing bis-fluorenyl zirconiumdichloride and bis-fluorenyl zirconium dimethyl. U.S. Pat. No. 4,892,851and the New Journal of Chemistry, Vol. 14, pages 499-503, dated 1990,the disclosures of which are incorporated herein by reference, eachdisclose preparing a metallocene from the ligand1,1-dimethylmethylene-1-(fluorenyl)-1-(cyclopentadienyl). The NewJournal of Chemistry article also discloses preparing a similar compoundin which the cyclopentadienyl radical has a methyl substituent in thenumber 3 position. The term fluorenyl as used herein refers to9-fluorenyl unless indicated otherwise.

An object of the present invention is to provide certain newfluorenyl-containing metallocenes. Another object of the presentinvention is to provide a method for preparing new fluorenyl-typemetallocenes. Still another object of the present invention is toprovide polymerization catalysts employing fluorenyl-type metallocenes.Still yet another object of the present invention is to provideprocesses for the polymerization of olefins using fluorenyl-typemetallocene catalyst systems. Still yet another object of the presentinvention is to provide polymers produced using suchfluorenyl-containing metallocene catalysts.

SUMMARY OF THE INVENTION

In accordance with the present invention, there are provided newmetallocenes of the formula R"_(x) (FlR_(n))(CpR_(m))MQ_(k) wherein Flis a fluorenyl radical, Cp is a cyclopentadienyl, indenyl, tetrahydroindenyl, or fluorenyl radical, each R is the same or different and is anorgano radical having 1 to 20 carbon atoms, R" is a structural bridgelinking (FlR_(n)) and (CpR_(m)), M is metal selected from the groupconsisting of IVB, VB, and VIB metals of the Periodic Table, each Q isthe same or different and is selected from the group consisting ofhydrocarbyl or hydrocarbyloxy radicals having 1 to 20 carbon atoms andhalogens, x is 1 or 0, k is an integer sufficient to fill out theremaining valences of M, n is an integer in the range of 0 to 7, m is aninteger in the range of 0 to 7, further characterized by the fact thatif (CpR_(m)) is unsubstituted fluorenyl and x is 0, then n is 1 to 7,and if (CpR_(m)) is unsubstituted cyclopentadienyl or3-methylcyclopentadienyl and R" is 1,1-dimethyl-methylene, then n=1 to7.

In accordance with another aspect of the present invention, there isprovided a method for forming fluorenyl-containing metallocenescomprising reacting an alkali metal salt of the selected fluorenylcompound with a transition metal compound of the formula Mqk in thepresence of a non-halogenated solvent for the fluorenyl salt whichsolvent is non-coordinating with the transition metal halide.

In accordance with still another aspect of the present invention, thereis provided a process for the polymerization of olefins comprisingcontacting said olefins under suitable reaction conditions with acatalyst system comprising a fluorenyl-containing metallocene asdescribed above in combination with a suitable organoaluminumco-catalyst.

Still further in accordance with the present invention there is providedthe polymer products resulting from such polymerizations.

FIG. 1 is the ¹³ C NMR spectrum of a polymer produced by polymerizing4-methyl-1-pentene using (1-fluorenyl-1-cyclopentadienylmethane)zirconium dichloride as a catalyst.

DETAILED DESCRIPTION OF THE INVENTION

The novel metallocenes provided in accordance with the present inventionfall into two broad general categories. One category involvesmetallocenes in which a fluorenyl radical, either substituted orunsubstituted, is bonded to another cyclopentadienyl-type radical by abridging structure R". These metallocenes are referred to herein asbridged metallocenes. The other category deals with metallocenes whichare unbridged, that is the fluorenyl radical ligand and the othercyclopentadienyl-type ligands are bound to the metal but not to eachother. These metallocenes are referred to as unbridged metallocenes.Methods for preparing fluorenyl-containing cyclopentadiene-typecompounds which can be used in making the metallocenes are disclosed inthe aforementioned U.S. patent application Ser. No. 697,363.

The metal, M is selected from the group IVB, VB, or VIB metals of thePeriodic Table. The currently preferred metals include titanium,zirconium, hafnium, chromium, and vanadium. The R" can be selected fromany suitable bridging structure. Typical examples include hydrocarbyland heteroatom containing alkylene radicals, germanium, silicon,phosphorus, boron, aluminum, tin, oxygen, nitrogen, and the like. The R"bridge when hydrocarbyl can be aromatic in nature, such as a phenylsubstituted alkylene; however, the currently preferred modes employaliphatic alkylene bridges. The currently most preferred bridges arehydrocarbyl or heteroatom containing alkylene radical having 1 to 6carbon atoms. In an especially preferred embodiment k is equal to thevalence of M minus 2.

The substituents R can be selected from a wide range of substituents. Inthe preferred embodiments the substituents R are each independentlyselected from hydrocarbyl radicals having 1 to 20 carbon atoms. In aparticularly preferred embodiment, the hydrocarbyl radicals R are alkylradicals. More preferably the alkyl R radicals have 1 to 5 carbon atoms.Each Q is a hydrocarbyl radical such as, for example, aryl, alkyl,alkenyl, alkaryl, or arylalkyl radical having from 1 to 20 carbon atoms,hydrocarbyloxy radicals having 1 to 20 carbon atoms, or halogen.

Exemplary Q hydrocarbyl radicals include methyl, ethyl, propyl, butyl,amyl, isoamyl, hexyl, isobutyl, heptyl, octyl, nonyl, decyl, cetyl,2-ethylhexyl, phenyl, and the like. Exemplary halogen atoms includechlorine, bromine, fluorine, and iodine and of these halogen atoms,chlorine is currently preferred. Exemplary hydrocarboxy radicals includemethoxy, ethoxy, propoxy, butoxy, amyloxy, and the like.

Illustrative, but non-limiting examples of unbridged metallocenesfalling within the scope of the above formula include bis(1-methylfluorenyl) zirconium dichloride, bis(1-methyl fluorenyl) zirconiumdimethyl, bis(1-methyl fluorenyl) hafnium dichloride, bis(1-t-butylfluorenyl)zirconium dichloride, bis(2-ethyl fluorenyl) zirconiumdichloride, bis(4-methyl fluorenyl)zirconium dichloride, bis(4-methylfluorenyl)hafnium dichloride, bis(2-t-butyl fluorenyl) zirconiumdichloride, bis(4-t-butyl fluorenyl)zirconium dichloride,bis(2,7-di-t-butyl fluorenyl)zirconium dichloride,bis(2,7-di-t-butyl-4-methyl fluorenyl)zirconium dichloride, and thelike.

Illustrative, but non-limiting examples of metallocenes containingbridged fluorenyl ligands include for example(1,1-difluorenylmethane)zirconium dichloride, (1,2-difluorenyl)ethanezirconium dichloride, (1,3-difluorenylpropane)zirconium dichloride,(1,2-difluorenylethane)hafnium dichloride,(1,3-difluorenylpropane)hafnium dichloride,(1-fluorenyl-2-methyl-2-fluorenylethane)zirconium dichloride,dimethylsilyldifluorenyl zirconium dichloride, (1,2-di(1-methylfluorenyl)ethane)zirconium dichloride, (1,2-di(1-methyl fluorenyl)ethane) hafnium dichloride, (1,2-di(2-ethyl fluorenyl)ethane)zirconiumdichloride, (1,2-di(2-t-butyl fluorenyl)ethane)zirconium dichloride,(1,2-di(2-t-butyl fluorenyl)ethane)hafnium dichloride, (1,2-di(1-t-butylfluorenyl)ethane) zirconium dichloride, (1,2-di(4-methyl fluorenyl)ethane) zirconium dichloride, (1,2-di(4-methyl fluorenyl)ethane) hafniumdichloride, (1,2-di(4-t-butyl fluorenyl)ethane) zirconium dichloride,1-(fluorenyl)-1-(cyclopentadienyl)methane zirconium dichloride,1-(fluorenyl)-1-(cyclopentadienyl)methane hafnium dichloride,1-(2,7-di-t-butyl fluorenyl)-1-(cyclopentadienyl)methane zirconiumdichloride, (1-fluorenyl-2-cyclopentadienylethane)zirconium dichloride,(1-fluorenyl-2-(3-methyl cylcopentadienyl)ethane)zirconium dichloride,(1-fluorenyl-2-indenyl ethane)zirconium dichloride,(1-fluorenyl-2-indenyl ethane)hafnium dichloride,(1-fluorenyl-2-methyl-2-indenyl ethane)zirconium dichloride,(1-fluorenyl-2-methyl-2-indenyl ethane)hafnium dichloride,(bis-fluorenylmethane)vanadium dichloride, (1,2-difluorenylethane)vanadium dichloride, (1-fluorenyl-1-cyclopentadienyl methane)zirconium trichloride, (1-fluorenyl-2-methyl-2-(3-methylcyclopentadienyl)ethane)zirconium dichloride, (1-(1-methylfluorenyl)-2-(4-methyl fluorenyl)ethane)zirconium dichloride,(1-(2,7-di-t-butyl fluorenyl)-2-(fluorenyl)ethane)zirconium dichloride,(1,2-di(2,7-di-t-butyl-4-methyl fluorenyl)ethane)zirconium dichloride,and the like.

Particularly preferred metallocene species include bridged and unbridgedmetallocenes containing at least one substituted fluorenyl radical,i.e., there is at least one FlR_(n) wherein n is 1 to 7.

The inventive metallocenes as well as related metallocenes can beprepared by reacting an alkali metal salt of the bridged or unbridgedfluorenyl compounds with a suitable transition metal compound in asuitable solvent under suitable reaction conditions.

The term transition metal compound as used herein includes compounds ofthe formula MQk wherein Me, Q, and k are as defined above. Somenon-limiting examples include zirconium tetrachloride, hafniumtetrachloride, cyclopentadienyl zirconium trichloride, fluorenylzirconium trichloride, 3-methylcyclopentadienyl zirconium trichloride,indenyl zirconium trichloride, 4-methyl fluorenyl zirconium trichloride,and the like.

The currently preferred unbridged metallocenes are prepared by reactinga substituted fluorenyl alkali metal salt with an inorganic halide ofthe Group IVB, V B, VIB metals to form a bis(substituted fluorenyl)metal halide. In an especially preferred embodiment bridged fluorenylcompounds of the formula (FIRn)R"(CpRm) are used wherein Fl, R, R", andm are as defined above, and where n is 1 to 7, most preferably 1 to 4.

Metallocenes in which Q is other than a halogen can be readily preparedby reacting the halide form of the metallocene with an alkali metal saltof the hydrocarbyl or hydrocarbyloxy radical under conditions as havebeen used in the past for forming such ligands in prior artmetallocenes. See, for example, the aforemention J. Organomet. Chem.113, 331-339 (1976). Another approach involves reacting a compound ofthe formula MQk wherein at least one Q is hydrocarbyl or hydrocarbyloxywith the alkali metal salt of the bridged or unbridged fluorenylcompound.

One embodiment of the present invention involves carrying out thereaction of the fluorenyl-containing salt and the transition metalcompound in the presence of a liquid diluent which is non-halogenatedand non-coordinating toward the transition metal compound. Examples ofsuch suitable liquid include hydrocarbons such as toluene, pentane, orhexane as well as non-cyclic ether compounds such as diethylether. Ithas been found that the use of such non-halogenated non-coordinatingsolvents generally allows one to obtain large amounts of substantiallypure metallocenes and in a more stable form; and also often allows thereaction to be conducted under higher temperature conditions, than whenTHF is used as the diluent. In an especially preferred embodiment thefluorenyl-containing salt used as a ligand is also prepared in a liquiddiluent that is non-halogenated and non-coordinating toward thetransition metal.

The formation of the alkali metal salt of the bridged or unbridgedfluorenyl compound can be formed using generally any technique known inthe art. For example, such can be prepared by reacting an alkali metalalkyl with the cyclopentadienyl type compounds, the bridged compoundshaving two cyclopentadienyl-type radicals per molecule. The molar ratioof the alkali metal alkyl to the cyclopentadienyl type radicals presentcan vary, generally however, the ratio would be in the range of about0.5/1 to about 1.5/1, till more preferably about 1/1. Typically, thealkali metal of the alkali metal alkyl would be selected from sodium,potassium, and lithium, and the alkyl group would have 1 to 8 carbonatoms, more preferably 1 to 4 carbon atoms. Preferably if the fluorenylsalt is formed using tetrahydrofuran (THF) as the liquid solvent, thesalt is isolated and substantially all of the THF is removed before thesalt is contacted with the transition metal halide. The molar ratio ofthe bridged or unbridged fluorenyl compound to the transition metalcompound can vary over a wide range depending upon the results desired.Typically, however, when an unbridged fluorenyl compound is used, themolar ratio of the unbridged fluorenyl compound to the transition metalcompound is in the range of from about 1 to 1 to about 2 to 1 and when abridged fluorenyl compound is used the molar ratio of the bridgedfluorenyl compound to the transition metal compound is about 1 to 1.

The resulting metallocene can be recovered and purified usingconventional techniques known in the art such as filtration, extraction,crystallization, and re-crystallization. It is generally desirable torecover the metallocenes in a form that is free of any substantialamount of by-product impurities. Accordingly, recrystallization andfractional crystallization to obtain relatively pure metallocens isdesireable. Dichloromethane has been found to be particularly useful forsuch recrystallizations. As a general rule, it has been found that themetallocenes based on unbridged fluorenyl compounds are less stable thanthe metallocene compounds formed from bridged fluorenyl compounds. Sincethe stability of the various metallocenes varies, it is generallydesirable to use the metallocenes soon after their preparation or atleast to store the metallocene under conditions favoring theirstability. For example the metallocenes can generally be stored at lowtemperature, i.e. below 0° C. in the absence of oxygen or water.

The resulting fluorenyl containing metallocenes can be used incombination with a suitable co-catalyst for the polymerization ofolefinic monomers. In such processes the metallocene or the co-catalystcan be employed on a solid insoluble particulate support.

Examples of suitable co-catalysts include generally any of thoseorganometallic co-catalysts which have in the past been employed inconjunction with transition metal containing olefin polymerizationcatalysts. Some typical examples include organometallic compounds ofmetals of Groups IA, IIA, and IIIB of the Periodic Table. Examples ofsuch compounds have included organometallic halide compounds,organometallic hydrides and even metal hydrides. Some specific examplesinclude triethyl aluminum, tri-isobutyl aluminum, diethyl aluminumchloride, diethyl aluminum hydride, and the like.

The currently most preferred co-catalyst is an aluminoxane. Suchcompounds include those compounds having repeating units of the formula##STR2## where R is an alkyl group generally having 1 to 5 carbon atoms.Aluminoxanes, also sometimes referred to as poly(hydrocarbyl aluminumoxides) are well known in the art and are generally prepared by reactingan organo hydrocarbylaluminum compound with water. Such a preparationtechniques are disclosed in U.S. Pat. Nos. 3,242,099 and 4,808,561, thedisclosures of which are incorporated herein by reference. The currentlypreferred co-catalysts are prepared either from trimethylaluminum ortriethylaluminum, sometimes referred to as poly(methyl aluminum oxide)and poly(ethyl aluminum oxide), respectively. It is also within thescope of the invention to use an aluminoxane in combination with atrialkylaluminum, such as disclosed in U.S. Pat. No. 4,794,096, thedisclosure of which is incorporated herein by reference.

The fluorenyl-containing metallocenes in combination with thealuminoxane co-catalyst can be used to polymerize olefins. Generallysuch polymerizations would be carried out in a homogeneous system inwhich the catalyst and co-catalyst were soluble; however, it is withinthe scope of the present invention to carry out the polymerizations inthe presence of supported forms of the catalyst and/or co-catalyst in aslurry or gas phase polymerization. It is within the scope of theinvention to use a mixture of two or more fluorenyl-containingmetallocenes or a mixture of an inventive fluorenyl-containingmetallocene with one or more other cyclopentadienyl-type metallocenes.

The fluorenyl-containing metallocenes when used with aluminoxane areparticularly useful for the polymerization of mono-unsaturated aliphaticalpha-olefins having 2 to 10 carbon atoms. Examples of such olefinsinclude ethylene, propylene, butene-1, pentene-1, 3-methylbutene-1,hexene-1, 4-methylpentene-1, 3-ethylbutene-1, heptene-1, octene-1,decene-1, 4,4-dimethyl-1-pentene, 4,4-diethyl-1-hexene,3,4-dimethyl-1-hexene, and the like and mixtures thereof. The catalystsare particularly useful for preparing copolymers of ethylene orpropylene and generally a minor amount, i.e. no more than about 12 molepercent, more typically less than about 10 mole percent, of the highermolecular weight olefin.

The polymerizations can be carried out under a wide range of conditionsdepending upon the particular metallocene employed, and the resultsdesired. Examples of typical conditions under which the metallocenes canbe used in the polymerization of olefins include conditions such asdisclosed in U.S. Pat. Nos. 3,242,099; 4,892,851; and 4,530,914; thedisclosures of which are incorporated herein by reference. It isconsidered that generally any of the polymerization procedures used inthe prior art with any transition metal based catalyst systems can beemployed with the present fluorenyl-containing metallocenes.

Generally the molar ratio of the aluminum in the aluminoxane to thetransition metal in the metallocene would be in the range of about 0.1:1to about 10⁵ :1 and more preferably about 5:1 to about 10⁴ :1. As ageneral rule, the polymerizations would be carried out in the presenceof liquid diluents which do not have an adverse affect upon the catalystsystem. Examples of such liquid diluents include butane, isobutane,pentane, hexane, heptane, octane, cyclohexane, methylcyclohexane,toluene, xylene, and the like. The polymerization temperature can varyover a wide range, temperatures typically would be in the range of about-60° C. to about 280° C., more preferably in the range of about 20° C.to about 160° C. Typically the pressure would be in the range of fromabout 1 to about 500 atmospheres or greater.

The polymers produced with this invention have a wide range of uses thatwill be apparent to those skilled in the art from the physicalproperties of the respective polymer. Some of the catalysts are usefulfor preparing syndiotactic polymers. The term syndiotatic polymer asused herein is intended to include those polymers having segments ofmore than 10 monomeric repeating units in which the alkyl group of eachsuccessive monomeric unit is on the opposite side of the plane of thepolymer. Generally, the polymer segments having such syndiotacticmicrostructure are formed of at least about 40 monomeric repeating unitsin which the position of the alkyl group relative to the plane of thepolymer alternates from one monomeric unit to the next monomeric unit.

A further understanding of the present invention, its various aspects,objects and advantages will be provided by the following examples.

EXAMPLES Example I Preparation of 1-methyl fluorene

Two different reaction schemes have been used to prepare 1-methylfluorene from fluoranthene. The reaction schemes can be illustrated bythe following flow diagram. Both schemes involve the use of 1-carboxylicacid fluorenone as a starting material. ##STR3##

To prepare the 1-carboxylic acid fluorenone, i.e. formula 1, 20.2 g (0.1m) of fluoranthene was dissolved in 150 ml of acetic acid at 90° C. Atthat temperature 200 ml of 30% aqueous H₂ O₂, was then added gradually.Then the reaction mixture was stirred for another 3 hours at thattemperature. At the beginning of the reaction, a light yellowprecipitate was formed that disappeared after some time. Then thereaction mixture was cooled to 0° C. in an ice bath. An orangeprecipitate was formed and filtered off. The filtrate was poured intocold diluted aqueous HCl. An orange yellow precipitate was formed whichwas washed twice with H₂ O and then dissolved in an aqueous NH₃ solutionin order to remove the unreacted fluoranthene. Then the mixture wasfiltered. When the filtrate was neutralized with HCl, an orangeprecipitate was formed. The precipitate, 1-carboxylic acid fluorenone,was filtered off and dried. The amount produced was 13.4 g.

Scheme I

About 0.76 g (0.02 mmol) of LiAlH₄ was suspended in a mixture of 75 mlof diethylether and 25 ml of tetrahydrofuran (dried over LiAlH₄). Themixture was cooled to 0° C. in an ice bath. Then 1.35 g (0.01 mmol) ofAlCl₃ was added in small portions and the mixture was stirred at roomtemperature for 15 min. Then 4.2 g (0.02 mmol) of the carboxylic acidfluorenone dissolved in 400 ml of tetrahydrofuran was added via adropping funnel while the reaction mixture was heated to reflux.Stirring was maintained for an additional 30 min. Then the reactionmixture was cooled to room temperature and the unreacted LiAlH₄ wasdestroyed with an aqueous solution of HCl. The organic phase was removedin vacuo. The solid, i.e. 1-hydroxymethyl fluorenone (formula 2), wasrecovered in the amount of 3.2 g. The raw 1-hydroxymethyl fluorenone canbe used without further purification. 2 g of palladium on carboncatalyst containing about 10 weight percent Pd was weighed into a flaskand 4.2 g (0.02 mmol) of the recovered 1-methanol fluorenone wasdissolved in 250 ml tetrahydrofuran and added to the flask. Thehydrogenation was conducted at room temperature with a slightoverpressure of H₂ until 1350 ml of H₂ was consumed. The reactionmixture was filtered and the solvent of the filtrate was removed invacuo. The creme colored residue was extracted with pentane, thesolution was filtered over silica, and the solvent removed in vacuo. Theresulting product, 1-methyl fluorene, was a colorless solid and formedin quantitative yield.

Scheme II

In the second route, the 1-carboxylic acid fluorenone is reduced usingthe palladium carbon catalyst in the same manner as described forconverting the 1-hydroxymethyl fluorenone to 1-methyl fluorene. Aquantitative yield of 1-carboxylic acid fluorene, i.e. formula 3, wasobtained. The volume of hydrogen consumed was 960 ml. This product wasthen reduced to 1-hydroxymethyl fluorene, i.e. formula 4, by using theLiAlH₄ and AlCl₃ as described for the production of the 1-hydroxymethylfluorenone. The 1-hydroxymethyl fluorene was then reduced using thepalladium carbon catalyst and hydrogen to yield 1-methyl fluorene.

Example II Preparation of 1-tert-butyl fluorene ##STR4##

About 2 g (0.01 mmol) of 1-carboxylic acid fluorene was suspended in 50ml of toluene. Then 4.6 ml AlMe₃ was added to the solution and thereaction mixture was refluxed for 10 hours. Upon heating, the reactionmixture formed a homogeneous solution. The reaction mixture was cooledto room temperature and then poured into ice cooled diluted aqueous HCl.The organic layer was separated, washed with H₂ O, and dried over Na₂SO₄. Then the solvent was removed in vacuo. The colorless residue wasextracted with pentane, the solution filtered over silica, and thesolvent removed in vacuo. The yield of 1-tert-butyl fluorene, formula 6,was quantitative.

Example III Preparation of 2-ethyl fluorene ##STR5##

In this reaction, 2-acetyl fluorene, i.e. formula 7, was converted into2-ethyl fluorene by hydrogenation. The hydrogenation reaction wasanalogous to the reaction used to convert the compound of formula 6 tothe compound of formula 5. The H₂ volume used was 970 ml. After theremoval of the solvent in vacuo, a creme colored solid was obtained. Itwas dissolved in pentane and the solution was filtered over silica.Pentane was removed in vacuo. The yield of 2-ethyl fluorene wasquantitative.

Example IV Preparation of 2-tert-butyl fluorene ##STR6##

In this reaction 2-acetyl fluorene was reacted with trimethyl aluminum.The methylation was analogous to the conversion of compound 3 tocompound 6 described in Example II. However, in this case, only atwo-fold excess of AlMe₃ was necessary. The 2-tert-butyl fluorene wasformed as a white solid in quantitative yield.

Example V Preparation of 4-methyl fluorene

Two different reaction schemes have been used to prepare 4-methylfluorene, i.e. formula 15. The schemes can be summarized as follows.##STR7##

Both schemes require 4-carboxylic acid fluorenone, formula 11, as astarting material. This compound was produced from phenanthrene using aprocedure similar to that disclosed in J. Org. Chem. 21, 243 (1956)except that no acetic anhydride was used. Instead, hydrogen peroxide andacetic acid were used to obtain a 67% yield of 2,2'-dicarboxylic acidbiphenyl, i.e. formula 10.

The biphenyl product of formula 10 was then oxidized using sulfuric acidin the manner taught in J. Am. Chem. Soc. 64, 2845 (1942) to obtain an82% yield of 4-carboxylic acid fluorenone, i.e. formula 11.

Scheme 1

The compound of formula 11 was reduced using LiAlH₄ and AlCl₃ in thesame manner as in Example I. The reaction produced an 80% yield of4-hydroxymethyl fluorenone, i.e. formula 14, which was then reducedusing hydrogen and the palladium carbon catalyst previously described. Aquantitative yield of 4-methyl fluorene resulted.

Scheme 2

The compound of formula 11 was reduced using hydrogen and the palladiumcarbon catalyst described previously. The reaction produced aquantitative yield of 4-carboxylic acid fluorene, i.e. formula 12.Reduction of this acid with LiAlH₄ and AlCl₃ resulted in an 80% yield of4-hydroxymethyl fluorene, i.e. formula 13. This product was then reducedusing hydrogen and the palladium carbon catalyst to produce aquantitative yield of 4-methyl fluorene.

Example VI Preparation of 4-tert-butyl fluorene

4-carboxylic acid fluorene was reacted with trimethylaluminum generallyas described in Example II to produce a 60% yield of 4-tert-butylfluorene.

Example VII Preparation of 2,7-bis(tert-butyl)-4-methyl fluorene##STR8##

2,7-bis(tert-butyl)-4-methylene chloride fluorene was reduced usinghydrogen and the palladium carbon catalyst to obtain a quantitativeyield of 2,7-bis(tert-butyl)-4-methyl fluorene.

Example VIII Preparation of 1,2-bis(9-fluorenyl)ethane ##STR9##

About 8.3 g (0.05 m) of fluorene was dissolved in 150 ml oftetrahydrofuran. Then 31.8 ml (0.05 m) of butyl lithium (1.6 molar inhexane) was added dropwise to this solution. After one hour, 2.3 ml(0.25 m) of dibromoethane in 25 ml of tetrahydrofuran was added. Thesolution was stirred for 3 hours. The yellow solution was washed with 50ml of an aqueous NH₄ Cl solution (5 g NH₄ Cl/50 ml H₂ O), then washedwith 50 ml of water and then the organic phase was dried over Na₂ SO₄.Then the solvent was removed in vacuo. The light yellow residue waswashed twice with 25 ml of pentane. The resulting product was white. Theyield was 12.5 g, i.e. a yield of about 70%, based on the moles offluorene reacted. The product was confirmed through ¹ H NMR, ¹³ C NMR,mass spectroscopy, and gas chromatography.

Example IX Preparation of 1-bromo-2-(fluorenyl)ethane ##STR10##

In this reaction, 8.3 g (0.05 m) of fluorene was dissolved in 150 ml oftetrahydrofuran. Then 31.8 ml (0.05 m) of butyl lithium (1.6 molar inhexane) was added dropwise to this solution. After one hour, thissolution was added gradually to a stirred solution of 9 ml (0.1 m) ofdibromoethane in 300 ml of pentane within 2 hours. Then the reactionmixture was treated with 50 ml of an aqueous NH₄ Cl solution, and thenwashed with 50 ml of water. The organic phase was dried over Na₂ SO₄.Then the solvent was removed in vacuo. The yellow residue was dissolvedin pentane. The pentane solution was filtered over silica. The solutionwas concentrated to about 20% of the original volume and then theproduct was crystallized at -30° C. A yield of 10.88 g of1-bromo-2-(fluorenyl)ethane was obtained. The product was characterizedthrough ¹ H NMR, ¹³ C NMR, and Mass spectroscopy.

Example X

A number of fluorenyl-containing metallocenes were prepared using eitherdiethyl ether or toluene as a solvent.

When diethyl ether was used as a solvent, about 1 millimole of therespective bridged or unbridged fluorenyl compound was dissolved in 200milliliters of ether. Then 1.6 molar methyllithium in diethyl ether wasadded to the solution to provide 1 millimole of methyllithium for eachmillimole of cyclopentadienyl-type radical. (An exception would be inthe case in which it was desired to produce a mono-valent salt of abridged fluorenyl compound. In such a case then only about 0.5 millimoleof methyl lithium would be used for each millimole ofcyclopentadienyl-type radicals.) The reaction mixture was stirred untilno additional methane gas was evolved. This was done at roomtemperature. Next the transition metal halide was added in smallportions to the solution of the fluorenyl salt. The amount of transitionmetal was about 0.5 millimoles when the fluorenyl compound was amonovalent salt and about 1 millimole when the fluorenyl compound was adivalent salt. The resulting solution was typically stirred for anadditional 30 minutes and then concentrated to about 50 milliliters andfiltered. The orange to red-colored solids remaining on the filter platewere dissolved in dichloromethane and the resulting solution wasconcentrated and recrystallized, generally at about -78° C.

In the runs prepared using toluene as the solvent, about 1 millimole ofthe bridged or unbridged fluorenyl compound was mixed in 250 millilitersof toluene. This was combined with methyllithium (1.6 molar in diethylether) in an amount sufficient to provide 1 millimole of methyllithiumfor the unbridged compounds and 2 millimoles of the methyllithium forthe bridged fluorenyl compounds. (Again the exception discussed in theprevious paragraph also applies.) Then the reaction mixture was heatedat reflux until no more methane gas was being released. The solution wasthen allowed to cool to room temperature. The transition metal halidewas then slowly added to the solution. Again, about 0.5 millimoles oftransition metal compound was employed with the divalent fluorenyl saltsand about 1 millimole was employed with the monovalent fluorenyl salts.The suspension was then stirred for about 30 minutes. The solution wasthen concentrated to about 50 to 75 milliliters and filtered. The orangeto red solids on the filter plate were dissolved in dichloromethane andthe resulting solution was concentrated and cooled to -78° C. to obtainthe metallocene as a solid precipitate.

Procedures of those general types have been used to prepare thefollowing metallocenes:

(1,2-difluorenyl ethane) zirconium dichloride; (1-fluorenyl-2-indenylethane) zirconium dichloride and hafnium dichloride;(1-fluorenyl-1-cyclopentadienyl methane)zirconium dichloride;(1-fluorenyl-1-cyclopentadienyl methane)zirconium trichloride,(1,2-di(2-tert butyl fluorenyl) ethane) zirconium dichloride and hafniumdichloride; (1,2-di(2-methyl fluorenyl)ethane) zirconium dichloride;(1,2-difluorenyl ethane) hafnium dichloride; bis (2,7-tertbutyl-4-methyl fluorenyl)zirconium dichloride; (1,3-difluorenyl propane)zirconium dichloride and hafnium dichloride;(1-fluorenyl-2-methyl-2-fluorenyl ethane) zirconium dichloride; dimethylsilyl difluorenyl zirconium dichloride; (1,2-di(1-methylfluorenyl)ethane) zirconium dichloride; (1,2-di(1-tert butylfluorenyl)ethane) zirconium dichloride and hafnium dichloride;(1,2-di(2-ethyl fluorenyl)ethane zirconium dichloride and hafniumdichloride; (1,2-di(4-tert butyl fluorenyl)ethane zirconium dichloride;(1-fluorenyl-2-cyclopentadienyl ethane) zirconium dichloride;(1-fluorenyl-2-(3-methylcyclopentadienyl) ethane zirconium dichloride;(1-fluorenyl-3-indenyl propane) zirconium dichloride;(1-fluorenyl-2-methyl-2-cyclopentadienyl ethane) zirconium dichloride;(1-fluorenyl-2-methyl-2-indenyl ethane) zirconium dichloride;(1-fluorenyl-2-methyl-2-(3-methylcyclopentadienyl)ethane) zirconiumdichloride; (1-(1-methyl fluorenyl)-2-(4-methyl fluorenyl)ethane)zirconium dichloride; (1-(1-tert butyl fluorenyl)-2-(4-tert butylfluorenyl) ethane) zirconium dichloride; bis (2,7-di-tert butyl-4-methylfluorenyl) zirconium dichloride; (1,2-difluorenyl ethane) vanadiumdichloride, (1,1-difluorenyl methane) vanadium dichloride, bis(1-methylfluorenyl) zirconium dichloride; bis (1-methyl fluorenyl) hafniumdichloride; bis(2-ethyl fluorenyl)zirconium dichloride; bis (4-methylfluorenyl) zirconium dichloride, and bis (4-methyl fluorenyl) hafniumdichloride.

Use of Fluorenyl Metallocenes

A number of fluorenyl-containing metallocenes prepared in accordancewith the present invention were evaluated for their effectiveness ascatalysts for the polymerization of olefins. The specific metallocenesevaluated are referred to in the following tables as follows:

    ______________________________________                                        Catalyst                                                                      ______________________________________                                        A        (1,2-difluorenyl ethane) zirconium dichloride                        B        (1-fluorenyl-2-indenyl ethane) zirconium dichloride                  C        (1-fluorenyl-1-cyclopentadienyl methane) zirconium                            dichloride                                                           D        (1,2-di(2-tertbutyl fluorenyl)ethane) zirconium                               dichloride                                                           E        bis (2,7-di-tertbutyl-4-methyl fluorenyl) zirconium                           dichloride                                                           F        (1-fluorenyl-1-cyclopentadienyl methane) zirconium                            trichloride                                                          H        (1-fluorenyl-2-methyl-2-indenyl ethane) zirconium                             dichloride                                                           I        (1,2-difluorenyl ethane) hafnium dichloride                          ______________________________________                                    

The polymerizations were carried out in an autoclave type reactor usingmethylaluminoxane as a cocatalyst. The source of the methylaluminoxanevaried. In some runs a 30 weight percent toluene solution obtained fromSchering was used. In other runs a 10 weight percent toluene solution ofthe methylaluminoxane obtained from Ethyl Corp was used. In a dry boxunder substantially inert conditions the solid metallocene was added toa serum vial and then a known quantity of the metallocene solution wasadded to the vial. The gram atom ratio of the aluminum in thealuminoxane to the metal in the metallocene was about 2200 to 1. Some ofthe resulting catalyst system solutions were used in more than onepolymerization. Accordingly, all the catalyst system solutions were notused immediately after preparation. For optimum results it is considereddesirable to use the catalyst system soon after preparation.

The catalyst system solution was added to the polymerization reactorwhich had been suitably prepared for the particular polymerization to beconducted. Typically for the polymerization of propylene the reactorcontained liquid propylene as the reaction diluent. For polymerizationsof ethylene or 4-methyl-1-pentene liquid isobutane diluent was employed.After the catalyst was charged then monomer and hydrogen, if employed,was added at room temperature. The reaction was then allowed to proceedfor a period of time at which the reactor was cooled in an attempt tomaintain a selected reaction temperature. In most cases after thepolymerization was complete the diluent was flashed off and the polymersolids recovered and characterized. In some cases where the polymer wasof low molecular weight or substantially all in solution the liquidwould be drained and the unreacted monomer, comonomer, and/or diluentremoved by evaporation.

Various characteristics of the polymer and the polymerization werecharacterized. Examples of characteristics determined in various casesinclude density in grams/ml (ASTM D1505-68); Melt Flow Index in grams ofpolymer/10 minutes (ASTM D1238-65T, Condition L); High Load Melt Indexin grams of polymer/10 minutes 190° C. (ASTM D1238, Condition E); MeltIndex in grams of polymer/10 minutes 190° C. (ASTM D1238, Condition E);heptane insolubles determined by the weight percent of insoluble polymerremaining after extraction with boiling heptane; melting point indegrees centigrade by Differential Scanning Calorimetry; molecularweights by size exclusion chromatography, i.e. weight average molecularweight referred to herein as Mw and number average molecular weightreferred to herein as Mn; heterogenity index determined by dividing Mwby Mn. The (SEC) size exclusion chromatography was conducted using alinear column capable of resolving the wide range of molecular weightsgenerally observed in polyolefins, such as polyethylene. The SEC used a1,2,4-trichlorobenzene solution of the polymer at 140° C. The intrinsicviscosity was calculated from the SEC using the Mark-Houwink-Sakradaconstants, i.e. k·MW^(a) in deciliters/gram, referred to in thefollowing tables as IV. Unless indicated otherwise the conditionsemployed for characterizing the various properties were the same foreach polymer evaluated. In some cases infrared and 13C NMR spectra weretaken of the polymer. The NMR spectra were conducted on a1,2,4-trichlorobenzene solution of the polymer. The base standard in theNMR spectra was 0 ppm based on tetramethylsilane.

Example XI Ethylene Polymerization With (1,2 difluorenylethane)zirconium dichloride

A number of polymerization runs were conducted to evaluate theeffectiveness of (1,2-difluorenylethane) zirconium dichloride as acatalyst for the polymerization of ethylene both alone and with acomonomer. The various polymerization variables and the results aresummarized in the following Table. The value reported for comonomer whenused in all the following tables refers to grams of the comonomer. alsoyield is in grams.

                                      TABLE I                                     __________________________________________________________________________    Run                                                                              Temp. ° C.                                                                   Catalyst mg.                                                                        ΔPC2                                                                       ΔPH2                                                                       Hexene                                                                            Time                                                                             Yield                                                                              HLMI/MI                                                                              Density                                                                           Mw × 10.sup.3                                                                HI IV                        __________________________________________________________________________    1  90    0.66  70 NA NA  20 29.7 HLMI = 0                                                                             0.9384                                                                            633  3.9                                                                              5.79                      2  70    0.66  70 25 NA  60 25.8 448/2.43                                                                             0.9732                                                                            114  21.8                                                                             1.32                      3  70    1     70 25 NA  60 31.9 668/1.42                                                                             0.9759                                                                            116  19.4                                                                             1.34                      4  70    1     50 25 NA  60 81   363.2/7.19                                                                           0.9698                                                                            71.9 10.6                                                                             7.1                       5  90    0.66  70 2.7                                                                              90  60 8.15 5.1/.0042                                                                            0.8981                                                                            170  46.6                                                                             2.03                      6  70    1.65  50 NA 90  70 161  HLMI = 0.13                                                                          0.8881                                                                            332  16.8                                                                             3.52                      7  70    3     135                                                                              10 50  45 130  288.5/0.5                                                                            0.9154                                                                            165  23.2                                                                             1.88                      8  70    1     70 25 50  60 72.5 900/7.97                                                                             0.9297                                                                            159  27.1                                                                             1.8                       9  70    1     70 25 25  60 62.1 waxy   0.9478                                                                            24.1 7.1                                                                              0.41                      10 70    1     150                                                                              25 50  60 79   79.6 MI                                                                              0.9307                                                                            53.5 8.9                                                                              0.79                      __________________________________________________________________________

The table demonstrates that the fluorenyl-containing metallocene iscapable of producing polymers of ethylene having a wide range ofproperties. In the absence of hydrogen the polymer was a very highmolecular weight material as evidenced by the low HLMI, i.e. High LoadMelt Index. The data further demonstrates that copolymerization ofethylene and hexene can result in lower density polymers.

Example XII Ethylene Polymerization with Various Bridged FluorenylMetallocenes

A number of ethylene polymerizations were also conducted using otherbridged metallocenes. The various polymerization variables and theresults are summarized in the following Table. Runs 4 and 5 from theprevious Table are included for comparison.

                                      TABLE II                                    __________________________________________________________________________       Type                                                                       Run                                                                              Catalyst                                                                          Temp.                                                                             Catalyst, mg.                                                                       ΔPC2                                                                       ΔPH2                                                                       Hexene                                                                            Time                                                                             Yield                                                                              HLMI/MI                                                                             Density                                                                           M × 10.sup.3                                                                 HI IV                       __________________________________________________________________________     4 A   70  1     50 25 NA  60 81   363.2/7.19                                                                          0.9698                                                                            7.9  10.6                                                                             7.1                      11 B   70  1.4   50 25 NA  60 100  811.8/19.6                                                                          0.9727                                                                            4.7   6.6                                                                             0.78                     12 C   70  1     70 25 NA  60 21   0.06 HLMI                                                                           0.9517                                                                            --   -- --                       13 C   70  2     250                                                                              25 NA  60 37   0.07 HLMI                                                                           0.9568                                                                            --   -- --                       14 C   70  2     70 3  90  60 137   18.3/0.15                                                                          0.8817                                                                            1.7   4.4                                                                             1.6                       5 A   70  0.66  70 2.7                                                                              90  60 8.15   5.1/0.042                                                                         0.8981                                                                            1    56.6                                                                             2.03                     __________________________________________________________________________

The Table demonstrates that (1-fluorenyl-2-indenyl ethane) zirconiumdichloride, i.e Catalyst B, and Catalyst C, i.e(1-fluorenyl-1-cyclopentadienyl methane) zirconium dichloride are alsosuitable for the polymerization of ethylene. Catalyst C gave a highermolecular weight material as indicated by the HLMI values. Run 14demonstrates that Catalyst C is also capable of producing a copolymer ofethylene and hexene. The particular copolymer produced in this run isparticularly unusual in that in contained 12.4 mole percent comonomerand a relative comonomer dispersity of 105.9. The mole percent comonomerand relative comonomer dispersity were determined from NMR spectroscopyusing the technique disclosed in U.S. Pat. No. 4,522,987, the disclosureof which is incorporated herein by reference. Such a polymer can bereferred to as a low density super random copolymer, i.e. a polymerhaving a super random distribution of the comonomer.

Example XIII Propylene Polymerization With Various FluorenylMetallocenes

A number of polymerizations of propylene were conducted using variousfluorenyl-containing metallocenes. The reaction variables and theresults are summarized in the following Table.

                                      TABLE III                                   __________________________________________________________________________       Type      Catalyst                                                         Run                                                                              Catalyst                                                                          Temp. ° C.                                                                   mg  ΔPH2                                                                       Time                                                                             Yield                                                                            MF Density                                                                           Mw × 10.sup.3                                                                HI IV Insolubles                                                                         M.P. ° C.             __________________________________________________________________________    15 C   60    3   NA 30 360                                                                              19.6                                                                             0.8843                                                                            83.3 3.6                                                                              0.78                                                                             96.6 132.6                        16 C   60    1   NA 60 230                                                                              14.6                                                                             0.8812                                                                            94   4.3                                                                              0.86                                                                             92.4 133.6                        17 C   60    1   3.5                                                                              60 431                                                                              15.6                                                                             0.8829                                                                            89.3 2.3                                                                              0.83                                                                             98.1 134.6                        18 C   70    1   10 60 400                                                                              27 0.8797                                                                            74.8 2.1                                                                              0.72                                                                             78.5 134.8                        19 C   70    1   5  60 16 wax                                                                              --  --   -- -- 94.7 133                          20 D   60    2.3 NA 50 270                                                                              -- <0.8740                                                                           51.6 2.5                                                                              0.55                                                                             93.4 --                           21 E   60    1.6 10 60 9.5                                                                              -- --  --   -- -- --   --                           22 E   23.4  1.6 0  60 0  -- --  --   -- -- --   --                           23 F   70    2.5 25 60 3  -- --  --   -- -- --   --                           24 F   70    2.5 25 60 5  -- --  --   -- -- --   --                           25 G   70    12  10 60 41 -- --  --   -- -- --   --                           26 B   70    5   10 60 460                                                                              -- --  --   -- -- --   --                           27 H   70    2   10 60 82 -- --  --   -- -- --   --                           28 A   70    3   10 5  30 -- --  --   -- -- --   --                           29 I   70    5.2 10 60 182                                                                              -- --  --   -- -- --   --                           __________________________________________________________________________

Table III demonstrates that Catalyst C, i.e.(1-fluorenyl-1-cyclopentadienyl methane) zirconium dichloride, can beused to produce a polymer from propylene. The data in runs 15-17 showsthat the polypropylene is highly crystalline as demonstrated by theheptane insolubles values. It is believed that the polymer contains highlevels of syndiotactic molecular structure.

Run 20 demonstrates that Catalyst D, i.e. (1,2-di(2-tert butylfluorenyl)ethane) zirconium dichloride can be used to produce acrystalline polypropylene.

Run 21 demonstrates that Catalyst E, i.e. the unbridged metallocenebis(2,7-di-tertbutyl-4-methyl fluorenyl) zirconium dichloride, producedonly a small amount of solid polypropylene at 60° C. Run 22 shows thatCatalyst E was not particularly effective at all at 0° C.

Run 23 and 24 employed a non-sandwich bonded metallocene, i.e. ametallocene in which only one of the cyclopentadienyl-type radicals wasbonded to the transition metal. The catalyst produced only about 3 to 5grams grams of solid polymer along with about 45 to 55 grams of lowmolecular weight propylene soluble polymer. Unless indicated otherwiseby the formula or other means, all the bridged metallocenes referred toherein are sandwich bonded.

Run 26 employed the bridged metallocene (1-fluorenyl-2-indenyl ethane)zirconium dichloride. Although this catalyst yielded 460 grams of solidpolymer 94.4 weight percent of the polymer was a low molecular weightxylene soluble polymer. Similarly, the bridged metallocene(1-fluorenyl-2-methyl-2-indenyl ethane) zirconium dichloride in Run 27yielded 82 grams of solid, 88 weight percent of which was low molecularweight xylene soluble material.

Runs 28 and 29 employed bridged metallocenes based on 1,2-difluorenylethane. Both the zirconium and the hafnium metallocenes yielded solidpolypropylene.

Example XIV

Catalyst C, i.e. (1-fluorenyl-1-cyclopentadienyl methane) zirconiumdichloride, was evaluated as a catalyst for the polymerization of4-methyl-1-pentene. The amount of the metallocene employed was 5 mg. Thepolymerization was conducted in the presence of hydrogen with thedifferential pressure of the hydrogen being 25. The polymerizationtemperature was 120° C. and the length of the polymerization was 2hours. The polymerization resulted in the production of 96.7 grams of asolid having a weight average molecular weight of 33,330; a heterogenityindex of 1.8; and a calculated intrinsic viscosity of 0.12. About 92weight percent of the solid was insoluble in boiling heptane. Thepolymer had a melting point of 197.9° C. A 13C NMR spectrum was taken ofthe polymer as recovered, i.e. without heptane solubles removed, and itindicated that the polymer contained a substantial amount ofsyndiotactic functionality. A copy of the ¹³ C NMR spectrum is providedin FIG. 1. Significant peaks were observed at about 22.8, 24.8, 26,31.8, 42.8, 43.1, 46.1, and 46.2 ppm. The intensity of the peak at 43.1ppm has greater than 0.5 of the total peak intensities in the range of42.0 and 43.5 ppm. The peak at about 46.2 ppm had a greater intensitythan any peak between the major peaks at 46.1 and 43.1 ppm. Further, thepeak at about 42.8 ppm had a greater intensity than any peak between themajor peaks at 46.1 and 43.1 ppm. These peak locations are relative to apeak of zero ppm for tetramethylsilane.

Example XV

Under conditions substantially as used in Example XIII, a run wascarried out attempting to polymerize 4-methyl-1-pentene with Catalyst A,i.e. the bridged catalyst (1,2-difluorenyl ethane) zirconium dichloride.In this case 7 mg of the catalyst was employed and 180 grams of solidatactic wax-like polymer was obtained.

A similar run was conducted substituting the unbridged metallocene,bis(2-methylfluorenyl) zirconium dichloride for Catalyst A in thepolymerization of 4-methyl-1-pentene. In this run 5 mg of themetallocene was used and 9.7 grams of solid polymer was recovered. Twosamples of the polymer were subjected to heptane extraction. Theextraction gave heptane insoluble values of 54.8 and 68.8. The catalystwas thus not as active as either the bridged Catalyst mentioned in thepreceding paragraph or bridged Catalyst A.

That which is claimed is:
 1. A metallocene of the formula(1-methylfluorenyl) (1 -methylfluorenyl) MQ_(k) where M is a metalselected from the group consisting of IVB and VB metals of the PeriodicTable, each Q is the same or different and is selected from the groupconsisting of hydrocarbyl, hydrocarbyloxy radicals having 1 to 20 carbonatoms, and halogen, and k is 1 or
 2. 2. A metallocene according to claim1 wherein M is titanium, zirconium, or hafnium.
 3. A metalloceneaccording to claim 2 wherein each Q is a halogen, methyl, or ethylgroup.
 4. A metallocene according to claim 1 which is a neutralmetallocene.
 5. A metallocene according to claim 1 wherein M iszirconium and each Q is chlorine and k is 2.